For the past 4 to 6 weeks, more than 30 dogs have died from a parvo-like illness in Otsego County, Michigan.

Parvo is a highly contagious viral disease of dogs, the disease is often fatal and is most common in puppies 6 to 20 weeks old.

Symptoms of parvo include bloody stool and vomiting, the dogs in Michigan have symptoms of parvo but have tested negative for the virus.

Additionally, owners of some of the dogs who have passed said their pets were vaccinated against the virus.

However, it's unclear if the dogs were properly vaccinated. The series of shots for parvo must be administered on a specific schedule and maintain a certain temperature to be effective.

Puppies under 2 years old are being affected by the mysterious illness at this time, and are passing after three days of showing symptoms.

The Michigan Department of Agriculture and Rural Development (MDARD) has partnered with Michigan

State University Veterinary Diagnostic Laboratory and the U.S. Department of Agriculture, as well as other local agencies to investigate the illness.

As of right now, MDARD is encouraging pet owners to make sure their dog's vaccinations are up to date and to avoid travel if the animal is showing signs of illness. .